brake lever to the grip

[geniusloerts]

well my master cylinder on my bike has decided to be nice and soft and not stop by bike well. Last night I changed the fluid and bled the calipers thinking that maybe some air had gotten in the lines somehow. after cheking everything out the lever pressure wasn't anybetter, so I figured I would do a test stop. I was going 30ph and hammered on the front brake to bring it to a stop. IT took me a goot 75 to come to a complete stop.

So instead of rebuilding, I am thinking about upgrading to something newer and better and hopefully without those 4 screws that always strip out....

any suggestions? I know that there needs to be some matching as far as piston size in the lever...what has worked for you guys and what hasn't?

[dbeardslee]

I just rebuilt the brakes on another members 79SF that had coaster brakes. I rebuilt the master cylinder, disassembled cleaned and reassembled the calipers, and installed stainless steel brake lines. I bled them, and since the master cylinder isn't level when mounted on the handlebar I took it off and had a friend hold it level while I did the final fill with brake fluid. If you get on 'em hard now it will almost throw you over the handlebars .

[Incubus]

Upgrading your master cylinder to something newer will not do any good if that is not the root of your problem. Have you taken the calipers apart and cleaned them out? It's a relatively easy job and can make a big difference. Are you running the original 30-plus year old rubber brake lines? They can get weak and expand too easily letting all your lever action escape into expanding rubber instead of pushing the caliper piston. Have you checked your brake pads to make sure they haven't worn beyond acceptable levels? Are you sure you have all the air out of the lines to BOTH calipers? If one side still has a bubble in it neither side will work right.

If this were my bike I would be looking at everything but the master right now. If your master is giving you consistent back pressure, even if it isn't giving you strong stopping power, then I think it may not be the problem at all. Whenever I've had a master go out it usually started leaking brake fluid and/or did not have consistent back pressure when I pulled on the lever.

JMHO.

Patrick

[Ken Talbot]

Just for something to do, grip one hand tightly around the brake line while you pump the brake lever with the other. This will give you a good demonstration of why you want to change to braided stainless steel lines.

[bikerphil]

Sometimes on these masters, after bleeding, a few air bubbles will remain up in the banjo bolt area. This can be resolved by removing the master from the handlebars (cover in place) and pointing the banjo bolt downward, then remove one of the calipers and compress the piston a bit, forcing those air bubbles back into the reservoir. Protect your fuel tank in case some brake fluid seeps out. HTH

[Incubus]

There is one other thing you could check. I just found this out the other day on my bike. The caliper mounting bolts are supposed to allow the caliper to move to center itself on the disks. If those bolts get corroded or rusty the caliper can't adjust and the brakes will behave poorly. I had a serious coaster brake on the rear of my '79 Standard. After I pulled that bolt and cleaned off several years worth of rust and corrosion the back brake worked fine.

JAT

Patrick

[petejw]

also theres an adj at the lever
for free play, if the gap is to big it will allow
the lever to touch the grip.
at 30mph you should be able to lock the front wheel up.